Leader pin assembly for die sets



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DA N/EL H. P0 WELL BY flaw/ ATTORNE Y5 NOV. 7 1967 D. R. POWELL LEADERPIN ASSEMBLY FOR DIE SETS Filed Jan. 19, 1966 United States Patent3,351,392 LEADER PIN ASSEMBLY FOR DIE SETS Daniel R. Powell, 4111 YorkAve. N., Minneapolis, Minn. 55422 Filed Jan. 19, 1966, Ser. No. 521,6896 Claims. (Cl. 308) This invention relates generally to improvements indie sets used in the metal stamping arts, and more particularly toimproved leader pin assemblies for die sets.

Leader pin assemblies generally, include pins or pillars which aresecured to one of a pair of cooperating punch and die holders, andadapted to move axially through guide elements in the other of saidholders. The purpose of the leader pins is to maintain accuracy ofregistration or alignment between cooperating punch and die elementsmounted on the punch and die holders respectively, during relativemovement therebetween, when mounted in a punch press or like stampingmachine. Heretofore, particularly in situations wherein the die setshave been disposed in a press for generally horizontal relativemovements toward and away from each other, the leader pin assemblieshave been subject to undue wear and early scoring and failure due to thedifficulty in providing and maintaining proper lubrication for the same.

An important object of this invention is the provision of a leader pinassembly having means for introducing and maintaining a continuoussupply of lubricant to the moving parts during the operation thereof.

Another object of this invention is the provision of a leader pinassembly having sealing means to minimize loss of lubricant from theassembly. Still another object of this invention is the provision of aleader pin assembly including bearing means having a lubricant passagearrangement whereby lubricant is applied uniformly over the entirecontact area between cooperating movable parts of the assembly.

Another object of this invention is the provision of a leader pinassembly which is relatively simple and inexpensive to produce, which ishighly eificient in operation, and which is rugged in construction anddurable in use.

The above, and still further highly important objects and advantages ofthis invention will become apparent from the following detailedspecification, appended claims and attached drawings. Referring to thedrawings, which illustrate the invention, and in which like referencecharacters indicate like parts through the several views:

FIG. 1 is a fragmentary view in axial section of a leader pin assemblyproduced in accordance with this invention;

FIG. 2 is a transverse section taken on the line 2--2 of FIG. 1, androtated 90 with respect to FIG. 1; and

FIG. 3 is an enlarged fragmentary section taken on the line 3--3 of FIG.1.

In the preferred embodiment of the invention illustrated, a die set isshown as comprising a commercially available punch holder 1 and a dieholder 2, these being shown fragmentarily. The holders 1 and 2 aregenerally plate-like members adapted to have cooperating punch and dieelements, not shown, mounted thereon, and to be mounted in aconventional punch press or the like, also not shown. One of the holders1 or 2 is adapted to be secured to the bolster of the press, the otherthereof being adapted to be operatively connected to the slide or ram ofthe press. The structure of the holders 1 and 2 is well known, andfurther detailed description and showing thereof is omitted, in theinterest of brevity. As is usually the case with die sets, the holders 1and 2 are provided with aligned apertures 3 and 4 respectively formounting and reception of the usual leader pins and leader pin bushings.

The leader pin assembly of the present invention com- 3,351,392 PatentedNov. 7, 1967 prises a leader pin element 5 and a tubular guide element6. At one end, the leader pin 5 is provided with a head portion 7 thatis machined to accurately fit the opening 3 in the holder 1, and acircumferential flange 8 which receives a plurality of mounting screwsor the like 9 that are screw threaded into threaded holes 10 in theholder 1.

The tubular guide element 6 is formed to provide a circumferentialflange 11 which abuts the adjacent surface of the holder 2, the flange11 being bored to receive a plurality of circumferentially spacedmounting screws 12 that are screw threaded into suitable threadedopenings in the holder 2 to anchor the guide element 6 to the holder 2.At its flanged end, the guide element 6 is counterbored to receive alocating collar 13 which accurately aligns the tubular element 6 withthe leader pin element 5.

A tubular bearing sleeve 14 is press-fitted or otherwise rigidly mountedin the guide element 6 and extends for the greater part of the length ofthe guide element 6, the bearing sleeve 14 preferably being made frombronze or other suitable bearing material and having an inner surface 15that is accurately ground or otherwise finished to have a close slidingfit with the leader pin element 5. A pair of inner and outer sealingrings 16 and 17 encompass the leader pin element 5 at the opposite endsof the bearing sleeve 14 and are of conventional and well-knownstructure. The sealing ring 16 is interposed between the flanged collar13 and the adjacent end of the bearing sleeve 14, the sealing ring 17being interposed between the opposite end of the bearing sleeve 14 and aretaining ring 18 that is secured to the adjacent end of the guideelement 6 by suitable means, not shown. The retaining ring 18 is formedto provide a circular recess which contains a wiper ring 19 of .felt orother suitable material which prevents dust or other foreign materialfrom being carried into the bearing sleeve 14 by the leader pin element5 during reciprocatory movement thereof relative to the guide elements 6and bearing sleeve 14. A generally cylindrical shield 21 is fitted atone end over the flange 8 of the leader pin element 5, the opposite endthereof loosely encompassing the tubular guide element 6, whereby toprotect the exposed portion of the leader pin element 5 againstparticles of foreign matter, such as dust, steel shavings and the like,from coming into contact with the exposed portion of the leader pinelement 5 and adhering thereto.

The inner surface 15 of the bearing sleeve 14 is circumferentiallychanneled to provide a pair of radially inwardly opening circumferentialgrooves 21 adjacent the opposite ends of the sleeve 14, and anintermediate groove 22 at the longitudinally central portion of thesleeve 14. The outer cylindrical surface of the bearing sleeve 14 isprovided with a pair of diametrically opposed grooves or channels 23that extend longitudinally for slightly less than the full length of thebearing sleeve 14. Preferably, the grooves or channels 23 are disposedat the top and bottom portions of the sleeve 14 when the leader pinassembly is axially horizontally disposed, as shown in FIG. 1. Thebearing sleeve 14 is further drilled or bored to provide radial passages24 and 25 which lead from the grooves 21 to the channels 23 and from thegroove 22 to the channels 23 respectively. The guide element 6cooperates with the grooves or channels 23 to provide oil passagescommunicating with the grooves 21 and 22 through the radial passages 24and 25, and is drilled to provide radial passage portions 26 and 27communicating with the lower and upper channels 23 respectively. Anaxially extending passage 28 communicates with the radial passage 26 andan inlet passage 29 which terminates in an inlet port 31) to which isapplied a conventional conduit fitting 31 provided with a conduit 32which may be assumed to be connected to a source, not shown, of liquidlubricant,

such as oil under pressure. A second axially extending passage 33extends from the radial passage portion 27 to a radial outlet pasage 34which terminates in an outlet port 35 to which is applied a fittingequipped conduit 36 that extends upwardly from the flange 11 of thetubular guide element 6 and to the upper end of which is mounted a flowindicator container 37 having a transparent wall 38 through whichcirculation of lubricant may be observed. A return line 36a is connectedto the flow indicator container 37 and may be assumed to lead the sourceof lubricant supply, to complete a circulatory lubrication system. Theouter ends of the passages 26, 27, 23 and 33 are closed by O-ringequipped threaded plugs or the like 39. Preferably, the pressure atwhich the oil is supplied to the leader pin assembly is preferably quitelow, the pressure being only sufiicient to maintain a proper circulationof lubricant through the various passages, grooves and channels in theguide element 6 and bearing sleeve 14.

With the above arrangement, wear on the leader pin element is minimizedto a point where the effective life thereof is greatly extended, andaccuracy of registration between die components mounted on the holders 1and 2 is accurately maintained over long periods of operation. While Ihave shown the described a commercial embodiment of my leader pinassembly, it will be understood that the same is capable of modificationwithout departure from the spirit and scope of the invention, as definedin the claims.

What is claimed is:

1. A leader pin assembly for the die sets comprising:

(a) a leader pin element and a cooperating tubular guide element,

(b) means for securing said elements in axial alignment each to adifferent one of a pair of cooperating punch and die holders,

(c) an axially extended bearing sleeve mounted in said guide element andhaving an inner cylindrical surface for axial sliding engagement withsaid pin element,

(d) said bearing sleeve having a plurality of axially spaced radiallyinwardly opening circumferential grooves in said inner cylindricalsurface,

(e) said guide element and sleeve defining fluid passage meanscommunicating with said grooves,

(f) said passage means including an inlet for reception of liquidlubricant under pressure and an outlet in spaced relation to said inlet,

(g) and a pair of annular sealing rings mounted in said guide elementone each at an opposite end of said sleeve and snugly encompassing saidpin element.

2. The leader pin assembly defined in claim 1 in which a pair of saidplurality of grooves are disposed one each adjacent each end of saidsleeve, and at least one of said plurality of grooves being disposedintermediate said pair of grooves.

3. The leader pin assembly defined in claim 2 in which said leader pinelement and tubular guide element are axially horizontally disposed,said inlet being disposed at the lower portion of said tubular guideelement, said outlet being substantially diametrically opposite saidinlet.

4. The leader pin assembly defined in claim 3 in which said passagemeans includes a pair of diametrically opposed upper and lower axiallyextending passages defined by said guide element and sleeve, and radialpassages in said sleeve connecting said axial passages with saidgrooves.

5. The leader pin assembly defined in claim 1 in which said leader pinelement and tubular guide element are axially horizontally disposed,said inlet and outlet being diametrically opposed, said inlet beingdisposed at the bottom portion of said guide element, said passage meansincluding a pair of diametrically opposed upper and lower axiallyextending passages defined by said guide element and sleeve, saidcircumferential groove being disposed one each adjacent an opposite endof said sleeve and one at the longitudinally central portion of saidsleeve, said passage means further including axially spaced radialpassages connecting said axially extending passages with said groovesand other passages connecting said inlet and outlet with said lower andupper axially extending passages respectively adjacent the radialpassage to the groove at the longitudinally central portion of saidsleeve.

6. The leader pin assembly defined in claim 4 in further combinationwith a flow indicator container connected to said outlet above the levelof said tubular guide element, said container having a transparent wallportion providing a visible indication of the flow of lubricant throughsaid passage means.

References Cited UNITED STATES PATENTS 2,523,358 9/1950 Conner 3085 X3,109,514 11/1963 Deflandre 3085 X 3,228,733 1/1966 Mangiavacchi 308-5MARTIN P. SCHWADRON, Primary Examiner.

ROBERT A. DUA, Assistant Examiner.

1. A LEADER PIN ASSEMBLY FOR THE DIE SETS COMPRISING: (A) A LEADER PINELEMENT AND A COOPERATING TUBULAR GUIDE ELEMENT, (B) MEANS FOR SECURINGSAID ELEMENT IN AXIAL ALIGNMENT EACH TO A DIFFERENT ONE OF A PAIR OFCOOPERATING PUNCH AND DIE HOLDERS, (C) AN AXIALLY EXTENDED BEARINGSLEEVE MOUNTED IN SAID GUIDE ELEMENT AND HAVING AN INNER CYLINDRICALSURFACE FOR AXIAL SLIDING ENGAGEMENT WITH SAID PIN ELEMENT, (D) SAIDBEARING SLEEVE HAVING A PLURALITY OF AXIALLY SPACED RADIALLY INWARDLYOPENING CIRCUMFERENTIAL GROOVES IN SAID INNER CYLINDRICAL SURFACE, (E)SAID GUIDE ELEMENT AND SLEEVE DEFINING FLUID PASSAGE MEANS COMMUNICATINGWITH SAID GROOVES, (F) SAID PASSAGE MEANS INCLUDING AN INLET FORRECEPTION OF LIQUID LUBRICANT UNDER PRESSUR AND AN OUTLET IN SPACEDRELATION TO SAID INLET, (G) AND A PAIR OF ANNULAR SEALING RINGS MOUNTEDIN SAID GUIDE ELEMENT ONE EACH AT AN OPPOSITE END OF SAID SLEEVE ANDSNUGLY ENCOMPASSING SAID PIN ELEMENT.